Recurring Homologous Solar Eruptions in NOAA AR 11429

TL;DR

This study analyzes three recurrent solar eruptions from NOAA AR 11429, highlighting the roles of magnetic flux cancellation, shearing motions, and magnetic topology in driving homologous eruptions over several days.

Contribution

It provides new insights into the physical processes behind recurrent homologous eruptions, emphasizing the importance of flux cancellation and magnetic topology in eruption mechanisms.

Findings

Persistent flux cancellation leads to recurrent eruptions.

Magnetic flux rope formation and reformation occur along the same PIL.

Magnetic reconnection at the same location facilitates eruptions.

Abstract

We present the study of three homologous solar eruptions from NOAA active region (AR) 11429 over four days. This large and complex AR divided into two relatively simple sub-regions: northeast (NE) and southwest (SW). Recurrent eruptions occurred from the SW sub-region over different evolutionary phases, which provided a unique opportunity to isolate the physical processes responsible for solar eruptions. Persistent shearing and convergence of opposite magnetic polarities led to continuous flux cancellation along the SW polarity inversion line (PIL). A filament persistently lying along the SW-PIL was observed to survive each eruption, which suggests the partial eruption of the magnetic system. Further, following the first and second eruptions, a sigmoidal magnetic structure of similar morphology was reformed along the SW-PIL. The photospheric motion of magnetic flux continuously injected and stored the negative helicity in the partially erupted magnetic system and built up the magnetic free energy for the successive eruptions. These results suggest that the shearing motion and magnetic flux cancellation of opposite fluxes were: (1) the dominant factor, irrespective of the evolutionary phase, that contributed to the recurrent homologous eruption, and (2) the key processes of forming the erupting structure, likely a magnetic flux rope, and its long-lasting continuation results in reformation of identical erupting structure. The study also finds that similar magnetic topology could result in the magnetic reconnection at the same location, and such flares during the precursor phase would help in the eruption by decreasing the constraint of overlying magnetic field.